[INFO] fetching crate futures-async-combinators 0.3.2...
[INFO] checking futures-async-combinators-0.3.2 against beta for pr-78714
[INFO] extracting crate futures-async-combinators 0.3.2 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate futures-async-combinators 0.3.2 on toolchain beta
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate futures-async-combinators 0.3.2
[INFO] finished tweaking crates.io crate futures-async-combinators 0.3.2
[INFO] tweaked toml for crates.io crate futures-async-combinators 0.3.2 written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate crates.io crate futures-async-combinators 0.3.2 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 9da96733bee02ce546637e80c42e7926974acc43a8179330ab44c4f8f15c8a28
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "9da96733bee02ce546637e80c42e7926974acc43a8179330ab44c4f8f15c8a28", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9da96733bee02ce546637e80c42e7926974acc43a8179330ab44c4f8f15c8a28", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9da96733bee02ce546637e80c42e7926974acc43a8179330ab44c4f8f15c8a28", kill_on_drop: false }`
[INFO] [stdout] 9da96733bee02ce546637e80c42e7926974acc43a8179330ab44c4f8f15c8a28
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 090ba55b04a75577c9d8f9678d7725467a104825904a5ff0687d01aa132aa2af
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "090ba55b04a75577c9d8f9678d7725467a104825904a5ff0687d01aa132aa2af", kill_on_drop: false }`
[INFO] [stderr]    Compiling memchr v2.2.1
[INFO] [stderr]    Compiling serde v1.0.101
[INFO] [stderr]    Compiling getrandom v0.1.12
[INFO] [stderr]     Checking futures-core-preview v0.3.0-alpha.19
[INFO] [stderr]     Checking futures-sink-preview v0.3.0-alpha.19
[INFO] [stderr]    Compiling bitflags v1.2.0
[INFO] [stderr]    Compiling rayon-core v1.6.0
[INFO] [stderr]     Checking futures-io-preview v0.3.0-alpha.19
[INFO] [stderr]     Checking itertools v0.8.0
[INFO] [stderr]     Checking crossbeam-queue v0.1.2
[INFO] [stderr]    Compiling syn v1.0.5
[INFO] [stderr]     Checking crossbeam-epoch v0.7.2
[INFO] [stderr]     Checking futures-channel-preview v0.3.0-alpha.19
[INFO] [stderr]     Checking futures-async-combinators v0.3.2 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(async_closure, gen_future, generators)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `futures-async-combinators`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "090ba55b04a75577c9d8f9678d7725467a104825904a5ff0687d01aa132aa2af", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "090ba55b04a75577c9d8f9678d7725467a104825904a5ff0687d01aa132aa2af", kill_on_drop: false }`
[INFO] [stdout] 090ba55b04a75577c9d8f9678d7725467a104825904a5ff0687d01aa132aa2af